THIS IS A SHANNON AWARD PROVIDING PARTIAL SUPPORT FOR THE RESEARCH PROJECTS THAT FALL SHORT OF THE ASSIGNED INSTITUTE'S FUNDING RANGE BUT ARE IN THE MARGIN OF EXCELLENCE. THE SHANNON AWARD IS INTENDED TO PROVIDE SUPPORT TO TEST THE FEASIBILITY OF THE APPROACH; DEVELOP FURTHER TESTS AND REFINE RESEARCH TECHNIQUES; PERFORM SECONDARY ANALYSIS OR AVAILABLE DATA SETS; OR CONDUCT DISCRETE PROJECTS THAT CAN DEMONSTRATE THE PI'S RESEARCH CAPABILITIES OR LEND ADDITIONAL WEIGHT TO AN ALREADY MERITORIOUS APPLICATION. THE ABSTRACT BELOW IS TAKEN FROM THE ORIGINAL DOCUMENT SUBMITTED BY THE PRINCIPAL INVESTIGATOR. DESCRIPTION (Adapted from applicant's abstract): The goal of the proposed research is to find genes required for axonal growth, pathfinding and target recognition using a mutagenetic approach. The animal model is the Drosophila optic nerve of the larva which provides a simple model of the aforementioned phenomena. The optic nerve follows a stereotyped path over a connecting bridge of cells and has two regions where growth cones pause and then make directional changes. Using a chemical mutagenesis screen a number of mutants have been isolated that effect the optic nerve at various points along its pathway. The molecular and genetic characterization of one of the mutations called abstract (abs) forms the heart of the proposal. The follow up studies that are proposed will (1) attempt to characterize abs to gain insights into its biochemical function; (2) analyze the phenotype of loss of function or gain of function mutations in the embryo and during imaginal disc formation in hopes of revealing its function; and (3) undertake a genetic analysis of abs as it interacts with other genes to define its role within a more complex background of altered proteins.